xref: /illumos-gate/usr/src/lib/libc/port/stdio/cuserid.c (revision 1da57d55)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma weak _cuserid = cuserid
31 
32 #include "lint.h"
33 #include <stdio.h>
34 #include <pwd.h>
35 #include <string.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38 #include <pthread.h>
39 
40 static char res[L_cuserid];
41 
42 char *
cuserid(char * s)43 cuserid(char *s)
44 {
45 	struct passwd *pw;
46 	struct passwd pwd;
47 	char buffer[BUFSIZ];
48 	char utname[L_cuserid];
49 	char *p;
50 	int cancel_state;
51 
52 	/*
53 	 * The UNIX98 Posix conformance test suite requires
54 	 * cuserid() to not be a cancellation point.
55 	 */
56 	(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
57 
58 	if (s == NULL)
59 		s = res;
60 	if ((p = getlogin_r(utname, L_cuserid)) != NULL) {
61 		(void) strlcpy(s, p, L_cuserid);
62 	} else if ((pw = getpwuid_r(getuid(), &pwd, buffer, BUFSIZ)) != NULL) {
63 		(void) strlcpy(s, pw->pw_name, L_cuserid);
64 	} else {
65 		*s = '\0';
66 		s = NULL;
67 	}
68 
69 	(void) pthread_setcancelstate(cancel_state, NULL);
70 	return (s);
71 }
72